05 21 2014 GEOL105 CHAPTER 1 Book Slides Hazard Disaster property Involve repetitive events Natural process and event that is a potential threat to human life or Hazardous event that occurs over a limited time in defined area Criteria for a natural disaster one or more of the following 10 or more people killed 100 or more people affected State of emergency is declared International assistance is requested Catastrophe time often years to recover o Ex Hurricane Katrina Massive disaster that requires significant amount of money and or 1990 s UN made an effort to address the increasing number of causalities International decade for natural hazard reduction and increased property damage from natural hazards Objective through mitigation they d minimize losses o Mitigation to reduce the effects of something Disaster Trends Recently there has been a dramatic increase in the cost of natural disasters Hurricanes Sandy Irene Japan earthquake Haitian earthquake Indonesian tsunami Hurricane Katrina Largest deaths tornadoes and wind storms 10 50 billion damages annually Geological Cycle Processes that produce and modify each earth materials such as rocks minerals and water Geological conditions govern the type location and intensity of natural processes Ex tectonic plates o most earth quakes volcanoes occur on the boundaries of o slopes of weak rocks shale more likely to slip Geological cycle includes groups of sub cycles o Tectonic cycle o Rock cycle o Hydrologic cycle o Biogeochemical cycle All interrelated o Tectonic provides water from volcanic processes heat energy needed to form change the earth materials transferred into biogeochemical cycles o Rock Hydrologic involved in many processes that transfer store chemical elements in water soil rock 1 Tectonic cycle earth s crust mountains Tectonic refers to large scale geological processes that deform Also produce land forms such as ocean basins continents and These processes are driven by forces deep within earth Tectonic plates large blocks of solid earth Responsible for the production distribution of rock and mineral Involves the creation movement destruction of tectonic plates resources 2 Rock cycle Rocks aggregates of one or more minerals o Mineral a naturally occurring crystalline substance with defined properties Largest of the geological subcycles Linked to all other subcycles o Depends on tectonic cycle for heat and energy o Depends on biochemical cycle for materials o Depends on hydrologic cycle for water Water used for processes of weathering erosion transportation deposition lithification of sediment Referred to as earth wide rock recycling process driven by earth s internal heat which melts the rocks subducted in the tectonic cycle Three types of rocks can be formed igneous sedimentary o Formed by crystallization of molten rock beneath and on metamorphic Igneous rocks earth s surface Sediment physically o Formed by weathering broken down chemically and o Vary in size from fine clay to boulder size o Then transported by wind ice water and gravity into depositional basins o Wind or water currents slow down ice melts or material is moved by gravity reaches flat surface sediment settles and accumulates deposition o Accumulated layers of sediment convert to solid rock lithification forming sedimentary rocks o Cementation and compaction as sediment is buried underneath other sediment o Under lithification sedimentary rocks may be metamorphosed altered in form by heat pressure chemically active fluids metamorphic rocks Lithificiation Metamorphic rocks o Altered in form o May be buried where pressure temp conditions force them to melt begin entire rock cycle all over Cycles depend on rock s environment Simpler Rock Cycle look up diagram Igneous formed by metamorphic rocks melting leading to crystallization of magma Metamorphic formed by sedimentary rocks under heat and pressure Sedimentary rocks formed by igneous rocks weathering at surface eroding transporting to water deposition of the sediment the burial compaction and compaction 3 Hydrological Cycle Movement of water from oceans to atmosphere and back again Driven by solar energy Operates by way of evaporation precipitation surface runoff and Water is stored in different compartments along the way o Oceans atmosphere rivers streams groundwater lakes ice subsurface flow caps glaciers Residence time time Diagram o Estimated average amount of time that a drop of water spends in any one compartment o Ranges from thousands of years to 9 days Very small amount of water is active at earth s surface at any one Helps move sort chemical elements in solution sculpt landscape weather rocks transport deposit sediments provide water sources Precipitation rain clouds surface runoff lake storage etc Precipitation infiltration or percolation filtering of water through ocean etc porous materials in soil Water from vegetation streams soil ocean transpiration water movement through a plant evaporation cloud formation 4 Biogeochemical Cycle Transfer or cycling of a chemical element s through the atmosphere lithosphere hydrosphere and biosphere o Atmosphere o Lithosphere o Hydrosphere o Biosphere Layer of gases surrounding earth Earth s rocky outer layer Oceans lakes rivers groundwater Part of earth where life exists Fundamental Concepts for Understanding Natural Processes as Hazards 1 Hazards are understandable from scientific evaluation 2 Risk analysis is important o Risk analysis estimates the probability that an event will occur the consequences 3 Linkages exist between different natural hazards as well as between hazards and the physical environment o Ex Earthquakes can produce landslides 4 Hazardous events that previously produced disasters are now producing catastrophes o Influenced by human activity greater population 5 Consequences of hazards can be minimized Scientific method to approach to Natural Hazards 1 Identify location of hazard where and size how big 2 Determine recurrence interval and probability of event how often 3 Estimate cost of event how much and determine risk 4 Make a forecast or prediction 5 Observe monitor any precursor activity and provide warning 6 Mitigate Educate Mitigate Educate The Cost of Natural Disasters is Increasing Through Time Why As population increases more people are hurt and more property is destroyed by natural disasters Disasters Are Now Becoming Catastrophes Human Population Growth World s population has more than tripled in the past 70 years Population
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